Coating the surface of solid materials may be conventionally performed by dipping the solid material into a liquid coating composition. This technique has been enhanced by floating the coating material on another liquid. As the coating material floats on the surface of the other liquid, a layer may be formed which will then coat as a more uniform thin layer on the object being coated. This technique has been applied to both sheet material as well as three dimensional objects.
Bothwell, U.S. Pat. No. 846,774, is a very old example demonstrating the concept of floating a thick layer of paint on water and then dipping a sheet or other object in the liquid to apply a thin film of paint as a permanent coating on the articles being treated. Also see Dewer U.S. Pat. No. 304,802 and Davis U.S. Pat. No. 2,087,504.
In more recent years, a number of variations on this method have been used with numerous devices for continuously coating objects. Several different additives to one or more reagents have been proposed. Loetecher, U.S. Pat. No. 1,931,667, discloses marbleizing the surfaces of objects by dipping the object into a water bath with a multiple oil color paint surface layer floating thereon. The colors in the oil paint may be applied in any design, preferably one with irregular patterns resembling marble. To keep the paints from flowing and to fix the design to the dipped object, Leetacher adds alum to a soapy water solution to form a scum which will bind the colors and fix them in a particular orientation. The color layers may then be cut in any shape and oriented as desired.
Various materials have been added to the floating paint surface to impart special visual effects. Other liquids have also been added to the floating paint layer to improve its uniformity and adhesion to the article being coated. For example, Bennett, U.S. Pat. No. 2,981,632, adds naphtha and other thinners to spread the floating oil colors on a water surface. Multiple paints or colors are used and materials may be added to impart different types of finishes.
Other surface effects have been provided to coating material. For example N,N-diethyl-meta-toluamide has been proposed to enhance the globule forming effect in Stimson, U.S. Pat. No. 4,490,413.
Dip coating methods have also employed soft water and a number of thinners such as turpentine, naphtha, etc. to form thin films of oil dyes on the surface of the water. One such example is Hidan, U.S. Pat. No. 4,091,126. The object resulting after coating has a marbleized surface on a solid article.
To thin paint, a large number of hydrophobic solvents have been proposed. An example is given in Bone, U.S. Pat. No. 1,343,387, using terpineol and kerosene. Other examples are given in Skinner, U.S. Pat. No. 3,245,821, using kerosene and naphtha among other materials, and Licata, U.S. Pat. No. 2,320,527, using turpentine, mineral spirits, naphtha and other non-polar organic solvents in paint to cause thinning of the paint.
Previous attempts with paints have found that paints do not spread on water in sufficiently thin layers in a manner which allows them to almost disappear on the surface and when adding new color will also spread and start to condense the transparent colors and form a design. Furthermore, the aforementioned techniques of the prior art have not been satisfactory for forming a thin paint surface on a coated object. Thus, a variety of attempts have been made to modify the conditions to use floating paint. Thick layers and a non-flowing layer of paint on a pasty support have been proposed. However, these techniques lack the flexibility and require artistic talent to paint a design on the surface before the object is contacted on the surface. Also movement of the design was not readily performed and the paint layer was much thicker.
Lead based paints were used in the past. In recent years, the toxic effects of lead have become of greater concern. However, the physical properties of lead-free paints differ from those of lead-containing paints and as a result the conditions need to be modified. Therefore, the use of lead-free paint would be a desirable product to use. However, a simple method for spreading a very thin mobile layer of paint on a water surface for coating of an object upon directly dipping an object was not achieved with sufficiently thin films of paints until the advent of the invention of my above-identified U.S. Pat. No. 5,348,766, which has served the industry very well and has proven to be highly successful.
In accordance with the invention of my above-identified U.S. Pat. No. 5,348,766, the water on which the paint is floated is first conditioned with borax. However, borax if accidentally eaten can be toxic and therefore desirably is to be avoided if possible, especially in conjunction with products and processes in which children are involved.